Type-writer chair.



A' PATENTBD JUNE 16, l903.

F. I. GHIGHESTBR. TYPE WRITER CHAIR. APPLIOATION FILED JUNI: a. 1902.

N0 MODEL.

n :1ER: comrwraumo., wAsN UNITED l STATES Patented June 16, 1903.

PATENT OFFICE.

TYPE-wRlTl-:R-CHAIR.

SPECIFICATION forming part of Letters Patent No. 730,875, dated June 16, 1903.

Application filed June 6, 1902. Serial No. IIOAOI. (No model.)

To all 1071/0771/ t may concern,.-

Be it known that I, FREDERICK I. CHICHES- TER, a citizen of the United States, residing at Poughkeepsie, in the State of New York, have-invented' certain new and useful Improvementsin Type-W`I'iters Chairs, of which the following is a specification.

My invention relates to chairs for typewriters and for other purposes.

Revolving chairs have been made with seats constructed to admit a rocking or tilting motion, and such chairs have also been made with a movable or swinging back capable of adjustment at different angles with respect to the seat. In the present improvement I have combined all three featuresin a simple structure requiring only one spring and with the mechanism comprised in but three other principal parts. n

In` the annexed drawings, which illustrate my invention, Figure l is a side elevation of the chair. Fig. 2 shows the side elevation, showing the chair in tilted condition. Fig. 3 shows the tilting mechanism as seen from beneath the seat. Fig. 4 is a vertical section taken on the line w :t of Fig. 3.

The chair is supported on a tripod A, having a socket at a, receivingr the axis-shaft D, common to revolving chairs and usually in form of a screw. I

The chair seat is supported on a metal frame comprised in three principal parts, which are vdesignated as the main frame, the spidergand the back-frame carrying the chairback. f

The main frame B is of general rectangular figure and composed ot side bars b and front and back bars b' b", which latter are adapted in shape for being secured to the under side of the chair C. The spider E maybe viewed as having three branches f,f' and f2, which at their center junction receive the shaft D, made fast thereto.

The back-frame F consists chielly ofa crossbar having a stout projection K at the midlength thereof for supporting the chair-back. The chair-back comprises the back proper, H, and a lever I, on which it is adjustable at dierent heights. This lever is connected at the lower end to the projection K of the backframe F by a pivot connection to admit of adjustment of the back H toward and away vwhich takes into notches formed in the projectiorrK and locks thetwo together. The

cross-bar G has lips g at'each end receiving pivotsj, lwherebyit is hinged to ears e of the main frame, and when the lever I is locked to the part K the parts G, H, I, and K, constituting the swinging chair-back, all move as one on the pivots ,7' as the center of motion, being restrained by means of a strong spring, in thisinstance represented bythe spiral spring M, the free end of which is attached to the extremity of an inner projection N on the cross-bar G, while the conned end is made fast to a part of the branchf of the spider E, preferably by attachment to a screw m, threadedr into a turned-up portion of such branchf by which to adjust its strength. A thumb-screw O, threaded into and through a lug on the back bar of the main frame, abuts against a side lug q on the part K and may be used to limit the movement of the chair-back. The location of the latch and of the screw at the rear side of the chair-seat brings them within easy reach, so that the occupant of the chair may adjust its condi,- tion without leaving the seat. o

Besidesthe swinging motion of the chairback, as above described, such back is capable of being'tilted with the seat, but upon another center of motion,which is located higher and nearer the front of the chair. For this purpose P is a brace serving to stifen the main frame, having ils lower side formed into a knife-edge, which sits into a shallow groove made across the top of the spider E. Such brace is prevented from leaving the groove laterally .by a rib 7L and is held down by hooks'u, made fast in the main frame and reaching under the spider. Y

When-only the chair-back is tilted on the pivots j as a center of motion, the extremity ot the projection N is free to swing toward and away from the spider E; but when the chair back and seat are to be tilted together the screw O, beforehamed, is turned hard against the side lug q on the part K, whereby the main frame carrying the chair-'seat is made rigid with the back-frame carrying the chair-back, and the whole structure will then tilt on the knife-edge center furnished by the IOO brace P, before described. When thus moving, themotion is controlled by thetension of the same spiral spring M before referred to.

The foregoing contrivance may be variously modified Within the invention.

I claim as my invention- 1. In a chair, the combination of a spiderframe, a tilting seat-frame pivoted to the spider-frame, a seat upon the seat-frame, a backframe pivoted to the seat-frame, a chair-back pivoted to the back-frame, means for adjustably varying the angle of the chair-back upon the back-frame, means for locking the backframe to the seat-frame, and yielding means for restraining both the simultaneous movement of the back-frame and chair-back, and the simultaneous movement of the backframe, chair back and seat.

2. In a revolving and tilting chair, the combination of a spider carrying the axis-shaft, a main frame of the chair-seat fnlcrumed on the spider, a chair-back, a back-frame carrying the chair-back arranged to swing on its own fulcrum consisting of pivots on the main frame, and a spring connecting the backframe and spider.

3. The combination with the spider, of the mainv frame pivoted to the spider, a backframe pivoted. to the main frame having at the rear a projection provided with notches, a chair-back pivotally attached to said projection on the back-frame, a latch carried by said chair-back engaging said notches for adjusting the chair-back at different angles with reference to the chair-seat, and for locking the two together, and a spring connecting the back-frame and the-spider.

FREDERICK I. CHICHESTER.

Witnesses:

EARLE H. SMITH, CHARLES G.`CoE. 

